The present invention is generally directed to apparatus and methods for processing materials and, more particularly, apparatus and methods for agglomerating chopped bundles of wet fiberglass strands into uniform segments.
In the manufacture of articles molded of plastic materials, it is known that fiberglass can be used to reinforce them so they have the requisite strength for their intended application. The mechanical strength of a fiberglass reinforced plastic article is dependent upon the quantity of fiberglass utilized as well as the characteristics of the glass fibers themselves. By controlling the quantity of fiberglass and the characteristics of the glass fibers, the strength attained can be balanced with the appearance of the plastic article.
In order to facilitate the manufacture of articles molded of plastic materials that are strengthened through reinforcement with fiberglass, techniques have been developed that involve the formation of bundles of fiberglass strands. These techniques typically involve forming a number of strands from a plurality of glass fibers that make up each strand, merging the strands and passing them through a set of pull rolls, and then chopping the strands into a plurality of discrete bundles. Essentially, the fiberglass strands, which may each be made up of several thousand glass fibers, are funneled together and then chopped to length, e.g., xe2x85x9 inch, xc2xc inch, xc2xd inch, etc.
As the bundles of fiberglass strands are being formed, they are xe2x80x9cwetxe2x80x9d, i.e., the glass fibers have a liquid coating that comprises on the order of approximately 7% to 19% moisture by weight. This xe2x80x9cwetxe2x80x9d material, when chopped, produces non-uniform, xe2x80x9cfuzzyxe2x80x9d bundles which is the result of the cutter tending to flatten the funneled strands from a cylindrical shape to an elliptical form which causes the fibers to be out of alignment with one another at the cut ends. With xe2x80x9cfuzzyxe2x80x9d ends, the chopped bundles of fiberglass strands do not flow evenly through conventional metering devices that are typically used to deliver them in quantity during plastic molding processes.
Because of the uneven flow of the chopped bundles through the metering devices, there is a limitation on the plastic molding process that reduces efficiency and increases cost.
For the foregoing reasons, there has been a need for apparatus and methods for agglomerating chopped bundles of wet fiberglass strands from fuzzy bundles into uniform segments so that they will flow evenly through metering devices at a greater rate of speed to increase efficiency and decrease cost by accommodating a higher rate of production during plastic molding processes.
In accordance with one aspect of the disclosure, a vibratory apparatus for agglomerating chopped bundles of wet fiberglass strands into uniform segments is provided that includes a container and a vibration generator. The container has a curved inner surface disposed about a generally horizontally extending longitudinal axis with a chopped bundle input end and an axially-spaced uniform segments output end opposite the input end. The container is mounted on a plurality of springs so as to be resiliently supported above a base surface, and the vibration generator produces a vibratory force to cause the chopped bundles of fiberglass strands to be directed in a generally rising and falling path of rolling movement along the curved inner surface of the container. The rolling movement occurs while the chopped bundles are being transported in the direction of the generally horizontal longitudinal axis from the input end toward the output end of the container. With the foregoing arrangement, the rolling movement of the chopped bundles provided by the vibratory apparatus produces uniform segments by causing agglomeration of the wet fiberglass strands.
In accordance with another aspect of the disclosure, a method of agglomerating chopped bundles of wet fiberglass strands into uniform segments is provided which includes providing a container having a curved inner surface disposed about a generally horizontally extending longitudinal axis and mounting the container on a plurality of springs to resiliently support the container above a base surface. A plurality of chopped bundles of wet fiberglass strands to be agglomerated are placed onto the curved inner surface at an input end of the container, and a vibratory force is produced to cause the chopped bundles of wet fiberglass strands to be moved from the input end toward an output end of the container. Additionally, the vibratory force causes the chopped bundles of wet fiberglass strands to be directed in a rising and falling path of rolling movement within the container whereby the rolling movement of the chopped bundles produces uniform segments by causing agglomeration of the wet fiberglass strands.
Other advantages and features of the disclosure will become apparent from a consideration of the following description taken in conjunction with the accompanying drawings.